Clamp for supporting umbrella



FIG. 1 is a left front perspective of a clamp for supporting umbrella, showing my new design;

FIG. 2 is a top plan view, thereof;

FIG. 3 is an elevational view of one side, thereof;

FIG. 4 is a bottom plan view, thereof;

FIG. 5 is an elevational view of one end, thereof;

FIG. 6 is an elevational view of the other side, thereof; and,

FIG. 7 is an elevational view of the other end, thereof. 

The ornamental design for a clamp for supporting umbrella, as shown. 